Pivoting axle system

Abstract

A pivoting axle system for an aerial lift vehicle includes a plurality of axles pivotally secured to the vehicle chassis at respective pivot points between a stowed position and a working position. Each axle is coupleable with a wheel assembly at distal ends thereof. Actuators are connected between the chassis and each of the plurality of axles, respectively, where the actuators are connected to the chassis at positions spaced from the pivot points, respectively. Additionally, each of the plurality of axles is independently controllable.

The invention claimed is: 
     
       1. A pivoting axle system for an aerial lift vehicle including a chassis, the pivoting axle system comprising:
 a plurality of axles pivotally secured to the chassis at respective pivot points between a stowed position and a working position, each axle coupleable with a wheel assembly at distal ends thereof, wherein each wheel assembly includes a wheel with a wheel tread; and 
 actuators connected between the chassis and each of the plurality of axles, respectively, wherein the actuators are connected to the chassis at positions spaced from the pivot points, respectively, 
 wherein each of the plurality of axles is independently controllable, and wherein each wheel assembly comprises a spindle and king pin mounted to a respective one of the plurality of axles, a steering pivot axis being offset from both a rotating axis of the wheel and a plane through a center of the wheel tread. 
 
     
     
       2. A pivoting axle system according to  claim 1 , further comprising actuator brackets connected to each of the plurality of axles, respectively, wherein the actuators are connected between the chassis and respective connecting points of the actuator brackets, and wherein the connecting points are positioned offset from longitudinal axes of the axles. 
     
     
       3. A pivoting axle system according to  claim 1 , wherein the actuators comprise hydraulic actuators. 
     
     
       4. A pivoting axle system according to  claim 1 , wherein the plurality of axles are disconnected from one another and operable separately from one another. 
     
     
       5. A pivoting axle system according to  claim 1 , wherein the plurality of axles comprise two front axles and two rear axles, the two front axles respectively supporting a corresponding two front wheel assemblies, and the two rear axles respectively supporting a corresponding two rear wheel assemblies. 
     
     
       6. A pivoting axle system according to  claim 5 , wherein in the working position, the two front wheel assemblies are spaced farther apart than in the stowed position, and the two rear wheel assemblies are spaced farther apart than in the stowed position. 
     
     
       7. A pivoting axle system for an aerial lift vehicle including a chassis, the pivoting axle system comprising:
 a plurality of axles pivotally secured to the chassis at respective pivot points between a stowed position and a working position, each axle coupleable with a wheel assembly at distal ends thereof; and 
 actuators connected between the chassis and each of the plurality of axles, respectively, wherein the actuators are connected to the chassis at positions spaced from the pivot points, respectively, 
 wherein each of the plurality of axles is independently controllable, wherein each of the plurality of axles comprises a multi-section telescoping assembly including a base section that is connected to the chassis and at least one movable section that is extendable and retractable relative to the base section, and wherein the wheel assemblies are connected to the axles at distal ends of the movable sections, respectively. 
 
     
     
       8. A pivoting axle system according to  claim 7 , wherein the multi-section telescoping assembly further comprises a ram connected between the base section and the movable section, the ram driving the movable section relative to the base section between an extended position and a retracted position. 
     
     
       9. An aerial lift vehicle comprising:
 a chassis supporting lift vehicle components; and 
 a pivoting axle system coupled with the chassis, the pivoting axle system including:
 a plurality of axles pivotally secured to the chassis at respective pivot points between a stowed position and a working position, each axle coupleable with a wheel assembly at distal ends thereof, wherein each wheel assembly includes a wheel with a wheel tread, and 
 actuators connected between the chassis and each of the plurality of axles, respectively, wherein the actuators are connected to the chassis at positions spaced from the pivot points, respectively, 
 wherein each of the plurality of axles is independently controllable, and wherein each wheel assembly comprises a spindle and king pin mounted to a respective one of the plurality of axles, a steering pivot axis being offset from both a rotating axis of the wheel and a plane through a center of the wheel tread. 
 
 
     
     
       10. An aerial lift vehicle according to  claim 9 , wherein the pivoting axle system comprises actuator brackets connected to each of the plurality of axles, respectively, wherein the actuators are connected between the chassis and respective connecting points of the actuator brackets, and wherein the connecting points are positioned offset from longitudinal axes of the axles. 
     
     
       11. An aerial lift vehicle according to  claim 9 , further comprising a drive system communicating with the wheel assemblies, wherein the actuators are configured to pivot the plurality of axles between the stowed position and the working position while the drive system drives the wheel assemblies. 
     
     
       12. A pivoting axle system for an aerial lift vehicle including a chassis, the pivoting axle system comprising a pair of front axles supporting a corresponding pair of front wheels with wheel treads and a pair of rear axles supporting a corresponding pair of rear wheels with wheel treads, the front and rear axles being pivotally secured to the chassis at respective pivot points, wherein the front and rear axles are selectively positionable between a transport position, where the front wheels are a first distance apart from each other and the rear wheels are a second distance apart from each other, and a working position, where the front wheels are a third distance apart from each other and the rear wheels are a fourth distance apart from each other, the third distance being greater than the first distance, and the fourth distance being greater than the second distance, each of the front and rear wheels being connected to the front and rear axles, respectively, with a spindle and king pin, wherein a steering pivot axis of each of the wheels is offset from both a rotating axis of the wheel and a plane through a center of the wheel tread. 
     
     
       13. A pivoting axle system according to  claim 12 , wherein each of the front and rear axles is independently controllable. 
     
     
       14. A pivoting axle system according to  claim 13 , further comprising actuators connected between the chassis and each of the front and rear axles, wherein the actuators are connected to the chassis at positions spaced from the pivot points.